Electrochemical Reconstruction of Metastable Oxyhalide Realizing a Rechargeable Zn-CO<sub>2</sub> Battery.

Fan, Mengwen; Zhou, Zeyan; Liu, Xinyu; Lv, Lin; Li, Chunli; Liu, Tong; Li, Linfeng; Zhang, Xia et al. · Nano Lett · 2026

basic_science · Level V

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Abstract

Bismuth-based catalysts are highly promising for the CO<sub>2</sub> reduction reaction (CO<sub>2</sub>RR) because of their outstanding catalytic performance. However, precise engineering of the surface-interface electronic architecture in these catalysts to refine CO<sub>2</sub> adsorption and activation remains a critical hurdle. Herein, we synthesize various metastable oxyhalides, followed by <i>in situ</i> electrochemical reconstruction to form Bi<sub>2</sub>O<sub>2</sub>CO<sub>3</sub>/Bi<sub>2</sub>O<sub>3</sub> heterostructures with carbonate-bismuth-oxygen (CO<sub>3</sub>-Bi-O) heterosites. <i>In situ</i> and <i>ex situ</i> measurements and theoretical studies reveal that in these CO<sub>3</sub>-Bi-O heterosites electron accumulation in Bi zones and depletion in O regions create a localized interfacial dipole effect, promoting favorable CO<sub>2</sub> adsorption and activation. The resulting heterosites enhance CO<sub>2</sub>RR selectivity to formate (92.5%), with a 12.5% improvement at -1.2 V (vs RHE) over pure Bi<sub>2</sub>O<sub>3</sub>. The superiority of BiOBr-derived R<sub>Br</sub>-Bi<sub>2</sub>O<sub>2</sub>CO<sub>3</sub>/Bi<sub>2</sub>O<sub>3</sub> is demonstrated in a proof-of-concept Zn-CO<sub>2</sub> battery, yielding twice the power density of Bi<sub>2</sub>O<sub>3</sub>-derived l-Bi<sub>2</sub>O<sub>2</sub>CO<sub>3</sub>/Bi<sub>2</sub>O<sub>3</sub>. This work paves the way for electrochemical reconstruction strategies in novel CO<sub>2</sub>-based battery exploration.